AP BIOLOGY

Detailed explanation-1: -Leaves are classified as either alternate, spiral, opposite, or whorled. Plants that have only one leaf per node have leaves that are said to be either alternate or spiral. Alternate leaves alternate on each side of the stem in a flat plane, and spiral leaves are arranged in a spiral along the stem.

Detailed explanation-2: -Alternate, whorled, and opposite are the three kinds of phyllotaxy. In alternate phyllotaxy, individual leaves arise from each node on the stem of the plant. Example: sunflower, peepal, mustard, etc. In opposite phyllotaxy, pairs of leaves arise from each node.

Detailed explanation-3: -Three ranked means the leaves come out from three different ―sides‖ of the stem. A comparison of the typical flowers of the grass family (Poaceae), sedge family (Cyperaceae) & rush family (Juncaceae). In grasses, the individual flower is referred to as a floret.

Detailed explanation-4: -leaf arrangement. phyllotaxy-the arrangement of leaves on an axis. 2-ranked-arranged in 2 rows, one on either side of the stem or central axis. alternate-an arrangement with 1 leaf attached at each node. distichous-2-ranked, with alternate leaves arranged on opposite sides of a stem, not spirally arranged.